Material fatigue remains one of the most persistent challenges in engineering, responsible for an estimated 80% of structural failures across mechanical systems. In aerospace, automotive, and energy production, where lightweight yet durable components are essential, fatigue resistance is a decisive factor in design and safety. Recent collaborative research between City University of Hong Kong (CityU) and Shanghai Jiao Tong University has produced a significant advance: a 3D-printed aluminum alloy with unprecedented fatigue resistance.
Professor Lu Jian, Dean of the College of Engineering at CityU and Director of the Hong Kong Branch of the National Precious Metals Material Engineering Research Center, co-led the work. “The fatigue phenomenon in metals was discovered about two centuries ago. Since then, fatigue failure has become one of the most important issues in the lifespan and reliability of all dynamic mechanical systems, such as those in aircraft, automobiles and nuclear power plants,” he stated.
In conventional metals, fatigue strength typically measures less than half of tensile strength. The limitation arises from multi-scale defects that grow under cyclic loading, eventually forming cracks large enough to compromise the entire structure. This vulnerability is equally present in alloys produced by additive manufacturing, constraining their broader adoption.
To address this, the team employed Laser Powder Bed Fusion (LPBF), a widely used metal additive manufacturing technique, to fabricate a novel aluminum alloy from AlSi10Mg powders enhanced with titanium diboride (TiB2) nanoparticles. The resulting nano-TiB2-decorated AlSi10Mg alloy—referred to as NTD-Al—demonstrated fatigue resistance more than twice that of other 3D-printed aluminum alloys and exceeded the performance of high-strength wrought aluminum alloys.
Published in *Nature Materials* under the title “Achieving ultrahigh fatigue resistance in AlSi10Mg alloy by additive manufacturing,” the work was also highlighted in *Science* as a generalizable strategy for improving fatigue resistance in other alloys.
Micro-computed tomography revealed a continuous three-dimensional dual-phase cellular nanostructure throughout the alloy. This structure, averaging 500 nanometers in diameter, forms a volumetric nanocage that inhibits localized damage accumulation and delays fatigue crack initiation. Professor Lu explained, “The three-dimensional network of nano eutectic silicon (Si) generated by additive manufacturing inside the alloy due to rapid solidification could block the movement of dislocations, thus suppressing fatigue crack initiation. With controlled defects through process optimization, the fatigue limit of the bulk NTD-Al alloy is superior to that of all existing Al alloys.”
Fatigue testing confirmed the alloy’s exceptional performance: a fatigue resistance of 260 MPa, more than double that of other additively manufactured aluminum alloys. This high fatigue strength limit surpassed all known aluminum alloys, including conventional high-strength wrought variants with minimal metallurgical defects.
The alloy’s capabilities have already been demonstrated in prototype applications. Large thin-walled structures, such as aircraft engine fan blades designed for high fatigue strength, were fabricated from NTD-Al and successfully passed qualifying fatigue tests. Such components demand a balance of low weight and high durability, making the alloy’s properties particularly relevant to aerospace engineering.
Professor Lu emphasized the broader industrial implications: “These findings indicate the potential applicability of our alloy for the lightweight structures necessary in industries where fatigue properties are the key design criterion. Our alloy can help reduce weight by increasing the load efficiency of moving components.” He added, “Combined with the advantages of 3D printing, the latest discovery will boost lightweight design and reduce carbon emissions in modern industries. And the same strategy can be also used for other materials to help solve the fatigue failure challenge in metal additive manufacturing.”
By integrating nanoparticle reinforcement with precise additive manufacturing control, the research points toward a new generation of alloys capable of meeting the stringent demands of high-performance engineering sectors. The combination of LPBF’s rapid solidification and TiB2’s structural reinforcement offers a pathway to components that are not only lighter but significantly more resistant to fatigue-related failure.